1. Field of the Invention
Embodiments of the invention relate to silicon carbide semiconductor device that uses silicon carbide single crystals and a method of manufacturing a silicon carbide semiconductor device.
2. Description of the Related Art
Mainstream semiconductor devices employed as power devices conventionally use silicon as a semiconductor material. However, compared to silicon, silicon carbide (SiC), a wide-bandgap semiconductor, has physical properties such as a thermal conductivity that is 3 times that of silicon, a critical electric field strength that is 10 times that of silicon, and an electron drift velocity that is 2 times that of silicon. Thus, application of these properties as a power device capable of high-temperature operation and having a high dielectric breakdown voltage and low loss is being researched.
Among SiC devices, in power metal oxide semiconductor field effect transistors (MOSFETs) and insulated gate bipolar transistors (IGBTs), a nickel (Ni) silicide is typically used to obtain an ohmic contact with the surface side of the substrate. A method of manufacturing such is as follows. After a desired impurity layer is formed on a SiC substrate, a gate oxide film is formed, and a poly-silicon pattern is formed.
Subsequently, after an interlayer insulating film is formed, an opening is formed by etching, at a location where a contact is necessary. Thereafter, a titanium nitride (TiN) film to prevent Ni from permeating the interlayer insulating film is formed on the entire surface by reactive sputtering or the like to have a thickness of about 100 nm, and a window is opened by dry etching at a portion where a silicide is to be formed.
Subsequently, a Ni film is formed by sputtering or vapor deposition and rapid heat treatment is performed whereby a Ni silicide is formed (for example, refer to Japanese Patent No. 3888330).